It looks like the people in charge of Gmail Labs have decided to do a little spring (or more accurately, late winter) cleaning. They've removed a full 11 experimental features from Labs, with six of the bunch becoming regular Gmail features and the other five failing to make the cut. Many of the "graduated" features are ones you're probably familiar with, or can at least guess the functions of. Forgotten Attachment Detector, YouTube Previews, Custom Label Colors,